During operation of a circuit arrangement, for example of a security controller, it is also possible to monitor environmental parameters, in order to check whether the environmental parameters are possibly acting on the circuit arrangement in such a manner that the internal functional operation of the circuit arrangement could be disturbed. One example of environmental parameters such as these is very high or very low temperatures, which could disturb the functional operation. For this purpose, the temperature of the chip in which the circuit arrangement is arranged is normally monitored during operation.
This monitoring is used to ensure the functional reliability of the circuit arrangement. When an increased or decreased temperature is detected which is outside the normal operating range, the operation of the chip can be prevented or stopped.
Conventionally, the chip temperature is monitored by means of analog sensors. However, these sensors have the disadvantage that the chip area which is used and required for them is relatively large. This is contrary to the miniaturization of chips, since this chip area is no longer available for other functions.
The requirement for the invention results from these and other reasons.